HttpNavigationManager no longer uses NavigationException

src/Components/Components/src/PublicAPI.Unshipped.txt

@@ -10,4 +10,4 @@ Microsoft.AspNetCore.Components.SupplyParameterFromPersistentComponentStateAttri
 Microsoft.AspNetCore.Components.SupplyParameterFromPersistentComponentStateAttribute.SupplyParameterFromPersistentComponentStateAttribute() -> void
 Microsoft.Extensions.DependencyInjection.SupplyParameterFromPersistentComponentStateProviderServiceCollectionExtensions
 static Microsoft.AspNetCore.Components.Infrastructure.RegisterPersistentComponentStateServiceCollectionExtensions.AddPersistentServiceRegistration<TService>(Microsoft.Extensions.DependencyInjection.IServiceCollection! services, Microsoft.AspNetCore.Components.IComponentRenderMode! componentRenderMode) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
-static Microsoft.Extensions.DependencyInjection.SupplyParameterFromPersistentComponentStateProviderServiceCollectionExtensions.AddSupplyValueFromPersistentComponentStateProvider(this Microsoft.Extensions.DependencyInjection.IServiceCollection! services) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
+static Microsoft.Extensions.DependencyInjection.SupplyParameterFromPersistentComponentStateProviderServiceCollectionExtensions.AddSupplyValueFromPersistentComponentStateProvider(this Microsoft.Extensions.DependencyInjection.IServiceCollection! services) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!

src/Components/Endpoints/src/DependencyInjection/HttpNavigationManager.cs

@@ -7,11 +7,68 @@ namespace Microsoft.AspNetCore.Components.Endpoints;
 
 internal sealed class HttpNavigationManager : NavigationManager, IHostEnvironmentNavigationManager
 {
+    private const string _enableThrowNavigationException = "Microsoft.AspNetCore.Components.Endpoints.HttpNavigationManager.EnableThrowNavigationException";
+
+    private static bool _throwNavigationException =>
+        AppContext.TryGetSwitch(_enableThrowNavigationException, out var switchValue) && switchValue;
+
     void IHostEnvironmentNavigationManager.Initialize(string baseUri, string uri) => Initialize(baseUri, uri);
 
     protected override void NavigateToCore(string uri, NavigationOptions options)
     {
         var absoluteUriString = ToAbsoluteUri(uri).AbsoluteUri;
-        throw new NavigationException(absoluteUriString);
+        if (_throwNavigationException)
+        {
+            throw new NavigationException(absoluteUriString);
+        }
+        else
+        {
+            if (!IsInternalUri(absoluteUriString))
+            {
+                // it's an external navigation, avoid Uri validation exception
+                BaseUri = GetBaseUriFromAbsoluteUri(absoluteUriString);
+            }
+            Uri = absoluteUriString;
+            NotifyLocationChanged(isInterceptedLink: false);
+        }
+    }
+
+    // ToDo: the following are copy-paste, consider refactoring to a common place
+    private bool IsInternalUri(string uri)
+    {
+        var normalizedBaseUri = NormalizeBaseUri(BaseUri);
+        return uri.StartsWith(normalizedBaseUri, StringComparison.OrdinalIgnoreCase);
+    }
+
+    private static string GetBaseUriFromAbsoluteUri(string absoluteUri)
+    {
+        // Find the position of the first single slash after the scheme (e.g., "https://")
+        var schemeDelimiterIndex = absoluteUri.IndexOf("://", StringComparison.Ordinal);
+        if (schemeDelimiterIndex == -1)
+        {
+            throw new ArgumentException($"The provided URI '{absoluteUri}' is not a valid absolute URI.");
+        }
+
+        // Find the end of the authority section (e.g., "https://example.com/")
+        var authorityEndIndex = absoluteUri.IndexOf('/', schemeDelimiterIndex + 3);
+        if (authorityEndIndex == -1)
+        {
+            // If no slash is found, the entire URI is the authority (e.g., "https://example.com")
+            return NormalizeBaseUri(absoluteUri + "/");
+        }
+
+        // Extract the base URI up to the authority section
+        return NormalizeBaseUri(absoluteUri.Substring(0, authorityEndIndex + 1));
+    }
+
+    private static string NormalizeBaseUri(string baseUri)
+    {
+        var lastSlashIndex = baseUri.LastIndexOf('/');
+        if (lastSlashIndex >= 0)
+        {
+            baseUri = baseUri.Substring(0, lastSlashIndex + 1);
+        }
+
+        return baseUri;
     }
 }

src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.EventDispatch.cs

@@ -3,6 +3,7 @@
 
 using Microsoft.AspNetCore.Components.Rendering;
 using Microsoft.AspNetCore.Components.RenderTree;
+using Microsoft.AspNetCore.Components.Routing;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
@@ -84,6 +85,26 @@ private void SetNotFoundResponse(object? sender, EventArgs args)
         SignalRendererToFinishRendering();
     }
 
+    private void OnNavigateTo(object? sender, LocationChangedEventArgs args)
+    {
+        if (_httpContext.Response.HasStarted)
+        {
+            // We cannot redirect after the response has already started
+            RenderMetaRefreshTag(args.Location);
+        }
+        else
+        {
+            _httpContext.Response.Redirect(args.Location);
+        }
+        SignalRendererToFinishRendering();
+    }
+
+    private void RenderMetaRefreshTag(string location)
+    {
+        var metaTag = $"<meta http-equiv=\"refresh\" content=\"0;url={location}\" />";
+        _httpContext.Response.WriteAsync(metaTag);
+    }
+
     private void UpdateNamedSubmitEvents(in RenderBatch renderBatch)
     {
         if (renderBatch.NamedEventChanges is { } changes)

src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.cs

@@ -84,6 +84,7 @@ internal async Task InitializeStandardComponentServicesAsync(
         if (navigationManager != null)
         {
             navigationManager.OnNotFound += SetNotFoundResponse;
+            navigationManager.LocationChanged += OnNavigateTo;
         }
 
         var authenticationStateProvider = httpContext.RequestServices.GetService<AuthenticationStateProvider>();

src/Components/Server/src/Circuits/RemoteNavigationManager.cs

@@ -17,6 +17,9 @@ internal sealed partial class RemoteNavigationManager : NavigationManager, IHost
     private readonly ILogger<RemoteNavigationManager> _logger;
     private IJSRuntime _jsRuntime;
     private bool? _navigationLockStateBeforeJsRuntimeAttached;
+    private const string _enableThrowNavigationException = "Microsoft.AspNetCore.Components.Endpoints.HttpNavigationManager.EnableThrowNavigationException";
+    private static bool _throwNavigationException =>
+        AppContext.TryGetSwitch(_enableThrowNavigationException, out var switchValue) && switchValue;
 
     public event EventHandler<Exception>? UnhandledException;
 
@@ -88,7 +91,21 @@ protected override void NavigateToCore(string uri, NavigationOptions options)
         if (_jsRuntime == null)
         {
             var absoluteUriString = ToAbsoluteUri(uri).AbsoluteUri;
-            throw new NavigationException(absoluteUriString);
+            if (_throwNavigationException)
+            {
+                throw new NavigationException(absoluteUriString);
+            }
+            else
+            {
+                if (!IsInternalUri(absoluteUriString))
+                {
+                    // it's an external navigation, avoid Uri validation exception
+                    BaseUri = GetBaseUriFromAbsoluteUri(absoluteUriString);
+                }
+                Uri = absoluteUriString;
+                NotifyLocationChanged(isInterceptedLink: false);
+                return;
+            }
         }
 
         _ = PerformNavigationAsync();
@@ -123,13 +140,60 @@ async Task PerformNavigationAsync()
         }
     }
 
+    private bool IsInternalUri(string uri)
+    {
+        var normalizedBaseUri = NormalizeBaseUri(BaseUri);
+        return uri.StartsWith(normalizedBaseUri, StringComparison.OrdinalIgnoreCase);
+    }
+
+    private static string GetBaseUriFromAbsoluteUri(string absoluteUri)
+    {
+        // Find the position of the first single slash after the scheme (e.g., "https://")
+        var schemeDelimiterIndex = absoluteUri.IndexOf("://", StringComparison.Ordinal);
+        if (schemeDelimiterIndex == -1)
+        {
+            throw new ArgumentException($"The provided URI '{absoluteUri}' is not a valid absolute URI.");
+        }
+
+        // Find the end of the authority section (e.g., "https://example.com/")
+        var authorityEndIndex = absoluteUri.IndexOf('/', schemeDelimiterIndex + 3);
+        if (authorityEndIndex == -1)
+        {
+            // If no slash is found, the entire URI is the authority (e.g., "https://example.com")
+            return NormalizeBaseUri(absoluteUri + "/");
+        }
+
+        // Extract the base URI up to the authority section
+        return NormalizeBaseUri(absoluteUri.Substring(0, authorityEndIndex + 1));
+    }
+
+    private static string NormalizeBaseUri(string baseUri)
+    {
+        var lastSlashIndex = baseUri.LastIndexOf('/');
+        if (lastSlashIndex >= 0)
+        {
+            baseUri = baseUri.Substring(0, lastSlashIndex + 1);
+        }
+
+        return baseUri;
+    }
+
     /// <inheritdoc />
     public override void Refresh(bool forceReload = false)
     {
         if (_jsRuntime == null)
         {
             var absoluteUriString = ToAbsoluteUri(Uri).AbsoluteUri;
-            throw new NavigationException(absoluteUriString);
+            if (_throwNavigationException)
+            {
+                throw new NavigationException(absoluteUriString);
+            }
+            else
+            {
+                Uri = absoluteUriString;
+                NotifyLocationChanged(isInterceptedLink: false);
+                return;
+            }
         }
 
         _ = RefreshAsync();

src/Components/test/E2ETest/ServerRenderingTests/InteractivityTest.cs

@@ -1399,4 +1399,16 @@ public void CanPersistMultiplePrerenderedStateDeclaratively_Auto_PersistsOnWebAs
         Browser.Equal("restored 2", () => Browser.FindElement(By.Id("auto-2")).Text);
         Browser.Equal("WebAssembly", () => Browser.FindElement(By.Id("render-mode-auto-2")).Text);
     }
+
+    [Theory]
+    [InlineData(true)]
+    [InlineData(false)]
+    public void NavigatesWithInteractivityByRequestRedirection(bool controlFlowByException)
+    {
+        AppContext.SetSwitch("Microsoft.AspNetCore.Components.Endpoints.EnableThrowNavigationException", isEnabled: controlFlowByException);
+        Navigate($"{ServerPathBase}/routing/ssr-navigate-to");
+        Browser.Equal("Click submit to navigate to home", () => Browser.Exists(By.Id("test-info")).Text);
+        Browser.Click(By.Id("redirectButton"));
+        Browser.Equal("Routing test cases", () => Browser.Exists(By.Id("test-info")).Text);
+    }
 }

src/Components/test/E2ETest/ServerRenderingTests/NoInteractivityTest.cs

@@ -64,4 +64,18 @@ public void CanUseServerAuthenticationStateByDefault()
         Browser.Equal("True", () => Browser.FindElement(By.Id("is-in-test-role-1")).Text);
         Browser.Equal("True", () => Browser.FindElement(By.Id("is-in-test-role-2")).Text);
     }
+
+    [Theory]
+    [InlineData(true, true)]
+    [InlineData(true, false)]
+    [InlineData(false, true)]
+    public void NavigatesWithoutInteractivityByRequestRedirection(bool controlFlowByException, bool isStreaming)
+    {
+        AppContext.SetSwitch("Microsoft.AspNetCore.Components.Endpoints.EnableThrowNavigationException", isEnabled: controlFlowByException);
+        string streaming = isStreaming ? $"streaming-" : "";
+        Navigate($"{ServerPathBase}/routing/ssr-{streaming}navigate-to");
+        Browser.Equal("Click submit to navigate to home", () => Browser.Exists(By.Id("test-info")).Text);
+        Browser.Click(By.Id("redirectButton"));
+        Browser.Equal("Routing test cases", () => Browser.Exists(By.Id("test-info")).Text);
+    }
 }

src/Components/test/testassets/Components.TestServer/RazorComponents/Pages/Routing/RoutingTestCases.razor

@@ -1,5 +1,5 @@
 @page "/routing"
-<h3>Routing test cases</h3>
+<h3 id="test-info">Routing test cases</h3>
 
 <ul>
     <li>
@@ -24,12 +24,6 @@
         <a href="routing/complex-segment(value)">Complex segments</a>
     </li>
     <li>
-        <a href="routing/not-found-ssr">Not found page for Static Server Rendering</a>
-    </li>
-    <li>
-        <a href="routing/not-found-webassembly">Not found page for Interactive WebAssembly rendering</a>
-    </li>
-    <li>
-        <a href="routing/not-found-server">Not found page for Interactive Server rendering</a>
+        <a href="routing/ssr-navigate-to">Redirect on SSR page</a>
     </li>
 </ul>

src/Components/test/testassets/Components.TestServer/RazorComponents/Pages/Routing/SSRRedirection.razor

@@ -0,0 +1,17 @@
+@page "/routing/ssr-navigate-to"
+@using Microsoft.AspNetCore.Components.Forms
+@inject NavigationManager NavigationManager
+
+<p id="test-info">Click submit to navigate to home</p>
+<form method="post" @onsubmit="Submit" @formname="MyUniqueFormName">
+    <AntiforgeryToken />
+    <button type="submit" id="redirectButton" class="btn btn-primary">Redirect</button>
+</form>
+
+@code {
+    private void Submit()
+    {
+        NavigationManager.NavigateTo("/subdir/routing");
+    }
+}
+

src/Components/test/testassets/Components.TestServer/RazorComponents/Pages/Routing/SSRRedirectionStreaming.razor

@@ -0,0 +1,19 @@
+@page "/routing/ssr-streaming-navigate-to"
+@attribute [StreamRendering]
+@using Microsoft.AspNetCore.Components.Forms
+@inject NavigationManager NavigationManager
+
+<p id="test-info">Click submit to navigate to home</p>
+<form method="post" @onsubmit="Submit" @formname="MyUniqueFormName">
+    <AntiforgeryToken />
+    <button type="submit" id="redirectButton" class="btn btn-primary">Redirect</button>
+</form>
+
+@code {
+    private async Task Submit()
+    {
+        await Task.Delay(1000); // Simulate some async work to let the streaming begin
+        NavigationManager.NavigateTo("/subdir/routing");
+    }
+}
+